Liquid compositions based on polyglycolethers having a high boiling point

Abstract

A process is disclosed for the preparation of monoalkyl ethers of polyoxyalkyleneglycols having a boiling point greater than 290° C and suitable for use as a hydraulic brake fluid, wherein a mixture of ethylene oxide and propylene oxide is reacted in an anhydrous alkaline medium, and at elevated temperatures and with a monoalkylether of diethylene glycol, in a preferred weight ratio oxides/glycol-ether comprised between 1.2 and 1.8. Preferably, the monoalkylether of diethylene glycol is the monomethylether which may contain a small amount of monoethylene glycol. The reaction product may be adjusted as regards viscosity by dilution with a minor amount of an alkoxy triglycol, e.g., butoxy triethyleneglycol.

What is claimed is: 
     
       1. A process for the preparation of monoalkylethers of polyoxyalkyleneglycols, having a maximum viscosity of 1800 cSt at -40° c, an average molecular weight between 270 and 300, and a boiling point of from 290° to 310° C, wherein a mixture of ethylene oxide and propylene oxide in a weight ratio between 30:70 and 45:55 is reacted at 120°-150° C and under a pressure of from 3 to 10 atmospheres, and in an anhydrous alkaline medium catalyst, with a monoalkylether of diethylene glycol containing ethylene glycol, in a weight ratio: alkylene oxide/glycol-ether between 1.5 and 1.8 and thereafter diluting the product of the polyaddition with an alkoxy-triglycol, the alkoxy group of which has 1-4 carbon atoms, until the desired viscosity is obtained. 
     
     
       2. A process according to claim 1, wherein the monoalkylether of diethylene glycol is the monomethylether. 
     
     
       3. A process according to claim 2, wherein the monomethylether of diethylene glycol contains from 3-6% by weight of monoethylene glycol. 
     
     
       4. A liquid composition suited for use as an hydraulic brake fluid, having a boiling point between 290° and 310° C., a maximum viscosity of 1800 cSt. at -40° C., and consisting essentially of: (a) 80-100% by weight of the monoalkylether of polyoxyalkylene glycol with an average molecular weight between 270 and 300 obtained by reacting a mixture of ethylene oxide and propylene oxide in a weight ratio between 30:70 and 45:55, with a monoalkylether of diethylene glycol, in a weight ratio of alkylene oxides/glycol ether between 1.2 and 1.8 in the presence of an alkaline catalyst, at 120°-150° C. under a pressure of from 3 to 10 atmospheres, and   (b) 0-20% by weight of an alkoxy-triglycol, the alkoxy group having from 1 - 4 carbon atoms.   
     
     
       5. A liquid composition according to claim 4 wherein the alkoxy-triglycol is butoxy-triethyleneglycol. 
     
     
       6. The composition of claim 4 wherein said monoalkylether of diethylene glycol is the monomethylether of diethylene glycol. 
     
     
       7. The composition of claim 6 wherein said monomethylether of diethylene glycol contains from 0-6% by weight of monoethylene glycol.